Glycated hemoglobin in blood has served as an important index for the diagnosis, treatment, etc. of diabetes because it reflects previous blood glucose levels in vivo.
The determination of such glycated hemoglobin has been carried out, for example, by high performance liquid chromatography (HPLC), a minicolumn method, immunoassays, and the like. According to these methods, the amount or ratio of hemoglobin that has been glycated can be determined. Recently, an enzymic method that enables the determination of glycated proteins by means of a fructosyl amino acid oxidoreductase (FAOD) has been developed, and attempts have been made to determine an amount of hemoglobin that has been glycated (i.e., glycated hemoglobin) by this enzymic method.